Impairment of sea urchin sperm quality by UV-B radiation: predicting fertilization success from sperm motility

Sperm quality of the sea urchin, Anthocidaris crassispina, after exposure to environmentally realistic UV-B irradiances, was assessed by changes in sperm motility (measured by the computer-assisted sperm analysis (CASA) system), and related to subsequent fertilization success. Percentage motile sperm of A. crassispina declined significantly after exposure to a UV-B dose of 16.2 kJ m−2, while sperm motion velocity as measured by curvilinear velocity (VCL), straight line velocity (VSL), and average path velocity (VAP) showed significant reduction after exposure to a UV-B dose of 5.4 kJ m−2. A parallel study showed that fertilization success was significantly reduced after sperm were exposed to UV-B doses 5.4 kJ m−2. Notably, the four sperm motility parameters were strongly correlated with fertilization success (P<0.001), followed the increasing order: VSL (r=0.8)<%motile sperm (r=0.804)